Poly(arylene sulfide) resins, e.g., poly(phenylene sulfide) (PPS), have become well known in the art for their thermal resistance, chemical resistance and an excellent balance of physical properties for use in preparing a variety of compositions useful in preparing articles by injection molding or compression molding techniques. These resins are also useful in forming coating compositions which are applied to a variety of substrates. These coatings also have the desired qualities of thermal resistance and chemical resistance. It was further found that the crystallization behavior of the poly(arylene sulfide) was important in obtaining good properties from compositions comprising such poly(arylene sulfide) polymers. For example, in the injection molding of compositions comprising poly(phenylene sulfide) the desired good properties could be obtained by utilizing a high mold temperature such as from about 120.degree. to 204.degree. C., or by utilizing a cold mold (quenching) followed by an annealing step such as at about 205.degree. C. These techniques appeared to produce articles with the highest level of crystallinity in the poly(phenylene sulfide) resin in the composition.
More recently, thermoplastic composites employing poly(arylene sulfide) resins in the matrix have become increasingly important. The desirable properties of temperature resistance and solvent resistance are also evident in such composites and these properties as well as outstanding strength are also affected by the matrix crystallinity behavior.
For many manufacturers the hot mold procedure represents an added expense in the equipment and energy required to carry out such a procedure. Furthermore, the quench-annealing process may also require added special equipment and reduces the freedom of choice in the operating procedure.
It is an object of this invention to provide a method for treating a poly(arylene sulfide) to increase the melt crystallization temperature (T.sub.mc) of the poly(arylene sulfide).
It is a further object of this invention to provide a method for increasing the rate of crystallization of a crystallizable poly(arylene sulfide) composition at a given temperature.
It is a further object of this invention to provide a method for altering the crystalline morphology of poly(arylene sulfide) compositions.
It is a still further object of this invention to provide additives which, when admixed with compositions comprising a poly(arylene sulfide) and subsequently subjected to heating and cooling steps, promote the formation of a fine-grained crystalline morphology in the poly(arylene sulfide).
Another object of the invention is to provide a method for preparing a fiber reinforced thermoplastic resin matrix comprising a poly(arylene sulfide) and an additive which promotes the formation of a fine-grained cyrstalline morphology without the necessity of quench-annealing the resultant composite to obtain optimal properties. Another object is to provide poly(arylene sulfide) compositions.